Close to 9 years for the first 10M from https://news.ycombinator.com/item?id=1 to https://news.ycombinator.com/item?id=10000000

About 4 years for the next 10M from there to https://news.ycombinator.com/item?id=20000000

Approx. 2.5 years for the 10M after that to the current total number of posts and comments we have today.

That's pretty interesting to me.

I wonder if growth will continue, and for how long HN will be able to sustain its excellent signal to noise ratio.